Decarboxylative Peptide Macrocyclization through Photoredox Catalysis

A method for the decarboxylative macrocyclization of peptides bearing N‐terminal Michael acceptors has been developed. This synthetic method enables the efficient synthesis of cyclic peptides containing γ‐amino acids and is tolerant of functionalities present in both natural and non‐proteinogenic amino acids. Linear precursors ranging from 3 to 15 amino acids cyclize effectively under this photoredox method. To demonstrate the preparative utility of this method in the context of bioactive molecules, we synthesized COR‐005, a somatostatin analogue that is currently in clinical trials.     

Copper‐Mediated Decarboxylative Coupling of Benzamides with ortho‐Nitrobenzoic Acids by Directed C−H Cleavage

A copper‐mediated decarboxylative coupling of benzamides with ortho ‐nitrobenzoic acids by 8‐aminoquinoline‐directed C−H cleavage has been developed. This reaction proceeds smoothly with only a copper salt to produce the corresponding biaryl compounds in good yields. The products can be easily transformed into various nitrogen‐containing heterocyclic compounds. Moreover, the combination of copper and a suitable base promotes a decarboxylative C−H arylation and cyclization sequence to deliver phenanthridinone derivatives in one pot.